So he said he would most probably pick her because he's lonely and he knows she likes him.

Then you have to ask yourself, if your loneliness justifies your cause for taking some fancy little person into your life that you don't really care for but seems sweet enough to you to ease your pain. Then you have to ask yourself, what happens to such a transitional being? Where do they go, after you are done with them? If your loneliness justifies your cause for ultimately hurting them because you didn't want to be by yourself and just for those moments alone, you wanted to hold someone, and you wanted to be loved by someone. Like buffers or filters or a soft cushion to soften the blow for a little while. Like a game of some interest just to kill time while you wait. And if they willingly know what they really mean to you and know the consequences of such an unbalanced relationship, does it really absolve you from all blame and responsibility?

Is it selfish? And if it is, so what?

I think there will always be times when we will be alone, and we will have to face it and come to terms with it. I think there's so much more to life than trying to find love. Yes, it is a big part of life, but there's so much more. And there are other better and happier and healthier ways to take away your loneliness, than to make use of someone else (no matter how willing the other party is).

I think inside all of us, is a secret desire for some insidious pleasure that is nervous and tender, but that smashes everything. In fact at the end of such a senselessly emotionally needy relationship, you'll be even more lonely than ever. Lost without direction, moving on from one body to another, completely wasted with different tastes in your mouth and different scents lingering all over you that you don't even know where you begin or where they end. I think you'll be very devastated, or maybe very foolishly happy.